The BOS Foundation says it is the first time in its 25-year history that it has taken in an albino orangutan.

The five-year-old was in poor condition after being rescued but the foundation said she was now having a "great recovery" and had gained about 4.5 kilograms (about 10 pounds) in the past fortnight.

The orangutan - which was rescued in Kapuas Hulu district - is being cared for at BOS's rehabilitation centre, which is home to almost 500 orangutans.

Normal Bornean orangutans have reddish-brown hair.

BOS Foundation said they were examining albinism in great apes before deciding on the best course of action for Alba's future welfare.

"We can't simply place Alba in a forest area, nor in a sanctuary, without thoroughly examining all possibilities," said Jamartin Sihite, BOS Foundation CEO. "So far we have been unable to find any other example of an albino orangutan and we need to know more about her and her special situation."

The Bornean orangutan, which along with the Sumatran orangutan are Asia's only great apes, is classified by the International Union for Conservation of Nature as "critically endangered".

Around 100,000 are estimated to live on Borneo, which is divided between Malaysia, Brunei and Indonesia, according to the IUCN.

Their habitat has shrunk dramatically as the island's rain forests are increasingly turned into oil palm, rubber or paper plantations, and they are sometimes targeted by villagers who view them as pests.